radv/video: Encode rate control fixes
- Fix setting slice QP
- Fix temporal layer rate control
- Set VBV buffer size + level
- Improve rate control behavior so that it won't overshoot target bitrate
- Implement
VK_VIDEO_ENCODE_H26X_CAPABILITY_PER_PICTURE_TYPE_MIN_MAX_QP_BIT_KHR
- Fix
dEQP-VK.video.encode.h26X_i_p_not_matching_order